Pyridyl xanthates and methods for preparing the same

ABSTRACT

Novel pyridyl Xanthate compounds are prepared by the reaction of a polychloro-4-alkylsulfonyl pyridine or pentachloropyridine with an alkali metal salt of an alkylxanthic acid in the presence of an inert carrier as a reaction medium at a temperature of from about 20* C. to about 95* C. The novel compounds are active as pesticides.

United States Patent [1 1' Dunbar et al.

[4 1 Oct. 9, 1973 [22] Filed:

[ PYRIDYL XANTHATES AND METHODS FOR PREPARING THE SAME [75] Inventors:Joseph E. Dunbar; John W.

Zemba, both of Midland City, Mich.

[73] Assignee: The Dow Chemical Company,

. M sllandtMish- Feb. 17, 1972 21 Appl. No.: 227,279

- Related US. Application Data [62] Division of Ser. No. 65,741, Aug.20, l970, Pat. No.

[52] US. Cl 260/294.8 E, 260/294.8 F, 424/263 [51] Int. Cl C07d 31/50[58] Field of Search 260/294.8 E, 294.8 F

[56] References Cited UNITED STATES PATENTS 3,660,412 5/1972 Haugwitz260/294.8 E 2,731,487 1/1956 Bashour 260/294.8 E

Primary Examiner-Alan L. Rotman Attorney-C. Kenneth Bjork et al.

[ 5 7] ABSTRACT Novel pyridyl Xanthate compounds are prepared by 5Claims, No Drawings CROSS REFERENCE TO RELATED APPLICATION This is adivision of application Ser. No. 65,741, filed Aug. 20, 1970, now US.Pat. No. 3,674,795.

SUMMARY .OF THE INVENTION The present invention is directed toaseries ofnovel pyridyl xanthate compounds and to methods for their preparation.The novel compounds of the present inventiori are represented by thefollowing structural formula:

W. so... V 7 if. V wherein Z and Z each independentlyrepre sent -S(JO-R, 7 Mn chlorine (ar bromine with the proviso that one of'Z or Z isalways halogen;

R represents an alkyl group of from one to about 20,

2 same. both inclusive, w lka x n t.halqaryt; groups; "Mis'afilkaliniiflEaTi'Bh'fiBd X, R and n are as hereinbefore defined.

As used in the presentspecification and claims, the

term aryl" means phenyl or substituted phenyl groups, such as, forexample, tolyl, xylyl and the like. Suitable alkali metal cationsoperable in the present invention include sodium, potassium and thelike.

. The reaction of the pyridine and alkylxanthic acid reactants isconveniently carried out in the presence of an inert carrier as areaction medium. Representative and suitable inert carriers which can beemployed as reaction media include water, acetone, dimethylformamide,acetonitrile, carbon tetrachloride, chloroform, benzene, toluene, ethylmethyl ketone, methanol, ethyl acetate, methylene chloride and the like.The reaction ordinarily consumes the reactants in amountsreprepreferably 1 to about 12, both inclusive, carbonatoms;

X represents chlorine or bromine, and

n represents an integer of from 1 to 3, both inclusive.

As used in the present specification and claims, the term alkyl meanssaturated, monovalentaliphatic radicals, including straight andbranched-chain radicals of from one to twenty carbon atoms, asillustrated by, but not limited to, methyl, n-amyl, n-hexyl, 2-hept'yl,3-methyl-2-octyl, n-octyl, 2-nonyl, 2-tetradecyl, nhexadecyl, Z-octyl,n-octyl, 2-nonyl, Z-tetradecyl, nhexadecyl, 2-eicosanyl and the like.

The products of the present invention-are oils or crystalline solids atroom temperatures, of low solubilityiin water and of varying degrees ofsolubility in many com.- mon organic solvents. The novel compounds areuseful as pesticides and are especially adapted to be employed as activetoxicants in compositions for the control of various pests includingmicrobial organisms, such: as, for example, powdery and downy mildew,Pullularia pullulans, 'l'richophyton mentagrophytes, Mycobacteriumphlei, Bacillus subtilis, Candida pelliculosa and the like, andundesirable plant pests usch as spiny clotbur, pigweeds and the like. i

lnone embodiment of the present invention, the novel compounds wherein Zrepresents are readily prepared by a novel process wherein a pyridinecompound correspondingto the forrnula:

is reacted with an alkali metal salt-of an alkylxanthic acid of theformula:

' MSCOR l wherein, in the above and succeeding formulas,

T represents S0,R', chlorine or bromine; R represents loweralkyl groupsof from one to; about four carbon atoms, both inclusive, aryl groups'offrom about six to about eight carbon senting essentially equimolarproportions of each and, while not critical, the use of such amounts ispreferred. The reaction proceeds smoothly when conducted at temperaturesof from about 20 C. to about 40 C. and is preferably carried out at roomtemperature. While the reaction may be conducted over a wide range ofpressures, no particular advantage ordinarily results from the use ofsubatmospheric or superatmospheric pressures and the reaction istherefore ordinarily carried out at atmospheric pressure.

ln carrying out the reaction, the reactants are usually dispersed inseparate portions of inert carrier and the resulting dispersions aremixed together in any convenient fashion. The resulting reaction mass isgenerally maintained with agitation at room temperature for a sufficientperiod of time to allow substantial completion of the reaction, usuallyfrom about 1 hour to about 30'hours. Following the substantialcompletion of the reaction, the reaction mass is filtered to remove thealkali metal salt by-products formed during the course of the reactionand then evaporated under reduced pressure to obtain the desired productas a solid or viscous liquid residue. When water is employed as one ofthe inert carriers, a two-phase liquid reaction mass is formed; aftersubstantialcompletion of the reaction, the organic portion is separated,dried over anhydrous sodium sulfate and evaporated under reducedpressure as before. i

The solid products thus obtained can be further purilied by conventionaltechniques which include washing with a liquid which is a solvent forimpurities butnot for the product, recrystallization and the like. Manyof the viscous liquid residues obtained crystallize on standing to yieldthe product as a crystalline solid which can then be further purified asabove.

In a further embodiment of the present invention, the pqxslssmmyn wher Zi 4 are readily prepared by a novel process wherein penta-.chloropyridine is reacted with an alkali metal salt of an alkylxanthicacid of the type set forth hereinbefore. The reaction is carried out inthe presence of dimethylformamide as the reaction medium.

The reaction ordinarily consumes the reactants in amounts representingessentially equimolar propor tions of each, and, while not critical, theuse of such amounts is preferred. The reactants are contacted in" anyconvenient fashion and the resulting reaction mass is heated withstirring at a temperature of from about 80 C. to about 95 C. for aperiod of time sufficient to assure substantial completion of thereaction, usually from about 2 hours to about hours. Following theDESCRIPTION OF THE PREFERRED EMBODIMENTS The following examplesillustrate the present invention and the manner by which it can bepracticed, but as such, should not be construed as limitations upon theoverall scope of the same.

Example 1: S-(2,3,5,6-tetrachloro-4-pyridyl)ethylxanthate A solution of2,3,5,6-tetrachloro-4-methylsulfonylpyridine (29.5 grams, 0.100 mole) in200 milliliters of methylene chloride was combined with a solution ofpotassium ethylxanthate (24.0 grams, 0.150 mole) in 150 milliliters ofwater, and the resulting twophase reaction mixture was agitatedvigorously at ambient temperatures for about 20 hours. Following thecompletion of the reaction, the methylene chloride phase was separatedfrom the reaction mixture, dried over anhydrous sodium sulfate,'andevaporated to dryness under reduced pressure. As a result of theseoperations, the desired S-(2,3,5,6-tetrachloro-4-pyridyl)ethylxanthateproduct was obtained as a yellow crystalline substance. The product wasrecrystallized from a mixture of petroleum ether and methylcyclohexaneto give a pure white crystalline product melting at 95 C. Elementalanalysis calculated v for C H CLNOS, (percent): C, 28.50; H, 1.50;,N,4.16; S, 19.02. Found (percent): C, 28.7; H, 1.45; N, 4.1, S, 19.2.Example 2: S-(2,3,5,6-tetrachloro-4-pyridyl)sec.-butylxanthate Asolution of 2,3,5,6-tetrachloro-4-methylsulfonylpyridine (29.5 grams,0.100 mole) in 200 milliliters of methylene chloride was combined with asolution of sodium sec.-butylxanthate (25.8 grams, 0.150 mole) in 150milliliters of water, and the resulting two-phase reaction mixture wasagitated vigorously at ambient temperatures for about hours. Followingthe completion of the reaction, the methylene chloride phase wasseparated from the reaction mixture, dried over anhydrous sodium sulfateand evaporated to dryness under reduced pressure. As a result of theseoperations, the desired S-(2,3,5,6-tetrachloro-4-pyridyl) sec.-butylxanthate product was obtained as a light yellow oil which sooncrystallized upon standing; it was recrystallized form a mixture ofpetroleum ether and methylcyclohexane and the recrystallized materialmelted at 64.5 C. to 65.5 C. Elemental analysis calculated for C, H,ClNOS, (percent): C, 32,89; H, 2.48; N, 3.84; S, 17.56. Found (percent):C, 33.0; H, 2.50; N, 3.8; S,

Example 3: S-(2,3,5,6-tetrachloro-4-pyridyl)isopropylxanthate A Asolution of 2,3,5,6-tetrach1oro-4-methylsulfonylpyridine (29.5 grams,0.100 mole) in 100 milliliters of methylene chloride was combined with asolution of sodium isopropylxanthate (16.0 grams, 0.10 mole) in 100milliliters of water and the resulting two-phase reaction mixture wasagitated vigorously for about 24 hours at ambient temperatures. Uponcompletion of the reaction, the methylene chloride layer was separated,dried over anhydrous sodium sulfate, and evaporated to dryness undersubatmospheric pressure, leaving the product as a light yellow oil whichsoon crystallized on standing. TheS-(2,3,5,6-tetrachloro-4-pyridyl)isopropylxanthate product thus obtainedwas recrystal lized from ethanol; the recrystallized product melted at93.595.5f C.

Example 4: S-(2,3,5,6-tetrachloro-4-pyridyl-n-pentylxanthate A solutionof potassium n! -pentylxanthate (20.2 grams, 0.100 mole) in 200milliliters of water was added with stirring to a solution of2,3,5,6-tetrachloro- 4-methylsulfonylpyridine (29.5 grams, 0.100 mole)in 200 milliliters of methylene chloride. The resulting two-phase liquidreaction mixture was stirred vigorously at ambient temperatures for aperiod of about 3 hours after which period of time the methylene chloride phase was separated, dried over anhydrous magnesium sulfate andevaporated to dryness under reduced pressure. As a result of theseoperations, there was obtained a viscous liquid containing crystals ofunreacted sulfone starting material; the unreacted sulfone was removedfrom the oil by filtration and the remaining viscous liquid was dried invacuo. The S-(2,3,5,6-tetrachloro-4-pyridyl) n-pentylxanthateproduct wasrecovered as an oil having a refractive index (n of 1.1059. Elementalanalysis calculated for C H CENOS (percent): C, 34.84; H, 2.92; N, 3.69.Found (percent): C, 34.7; H, 2.90; N, 3.90 Example 5:S-(2,3,5,6-tetrachloro-4-pyridyl)2- methylbutylxanthate A solution ofpotassium 2-methylbutylxanthate (20.2 grams, 0.100 mole) in 150milliliters of water was added with stirring to a solution of2,3,5,6-tetrachloro- 4-methylsulfonylpyridine (29.5 grams, 0.100 mole)in 150 milliliters of methylene chloride. The resulting two-phasereaction mixture was agitated vigorously for about 2% hours;by'thereafter following the procedures I as set forth in Example 4, theS-(2,3,5,6-tetrachloro-4- pyridyl)-2-methylbutylxanthate product wasobtained as a viscous liquid having a refractive index (n) of 1.6041.elemental analysis calculated for C H CENOS, (percent): C, 34.84; H,2.92; N, 3.69.

' grams, 0.078 mole) in 100 milliliters of water was added with stirringto a solution of 2,3,5,6-tetrachloro- 4-methylsulfonylpyridine (22.0grams, 0.078 mole) in milliliters of methylene chloride. The resultingtwo-phase reaction mixture was stirred vigorously at ambienttemperatures for a period of about 2% hours, after which period of timethe methylene chloride phase was separated from the reaction mixture anddried over anhydrous magnesium sulfate. Removal of the methylenechloride by evaporation in vacuo left a clear yellow-green oil residuewhich was purified By exposure to column chromatography usingcyclohexane as the eluent and activated alumina as an adsorbent; the S-(2,3 ,5 ,6-tetrachloro-4-pyridyl l ethylpropylxanthate product wasobtained as a clear, light green liquid which crystallized uponstandingat room temperature. One recrystallization from n- .hexane gave thepurified product as a pale green crystalline solid which melted at 6974C. Example 7: S-(2,3,5,6-tetrachloro-4-pyridyl)-ndodecyl-xanthate Asolution of potassium n-dodecylxanthate (21.0 grams, 0.07 mole) in 200milliliters of water was added with stirring to a solution of2,3,5,6-tetrachloro-4- methylsulfonylpyridine (21.0 grams, 0.07 mole)in100 milliliters of methylene chloride and the resulting twophasereaction mixture was stirred vigorously at ambient temperatures forabout 2 hours; by thereafter following the procedures as set forth inExample 6, the desired S-(2,3,5,6-tetrachloro-4-pyridly)ndodecylxanthate product was obtained as a viscous oil. A portion of theoil was further purified by additional exposure to column chromatographyusing cyclohexane as the eluent and activated alumina as an adsorbent:the-pruified product was a yellow-green liquid having a refractive index(n) of 1.5650. Elemental analysis calculated for C ,H, .,Cl,NOS(percent): C, 45,29; H, 5.28; N, 2.93. Found (percent): C, 45.8; H,5.44; N, 3.1. Example 8: S-(2,3,5-trichloro-4-pyridyl)isopropylxanthateA solution of sodium isopropylxanthate (20.0 grams, 0.13 mole) in 500milliliters of acetone was combined with a solution of2,3,5-trichloro-4-methylsulfonylpyridine (26.0 grams, 0.10 mole) in 100milliliters of acetone; the resulting reaction mixture was stirred forabout eight hours at ambient temperatures. Following the above timeperiod, the reaction mixture was filtered to remove the sodiummethanesulfinate by-product formed during the course of the reaction.Concentration of the filtrate by evaporation under subatmosphericpressure yielded the crude product of the desiredS-(2,3,5-trichlor0-4-pyridyl')-isopropylxanthate; it was recrystallizedfrom methanol and the recrystallized material melted at 7476 C. I iExample 9: S-(2,3,5-trichloro4- pyridyl)isobutylxanthate I A solution ofsodium isobutylxanthate (18.0 grams, 0.10 mole) in 400 milliliters ofacetone was combined with a solution of2,3,5-trichloro-4-methylsulfonylpyridine (26.0 grams, 0.10 mole) in 100milliliters of acetone and the resulting reaction mixture was stirredunder ambient temperature conditions for a period of about 16 hours.Followingthe completion of the reaction, the reaction mixture wasfiltered to remove the sodium methanesulfinate by-product formed-duringthe v course of the reaction and the filtrate was evaporated 'to drynessunder subatmospheric pressurre, leaving aresidual oil. The residual oilthus obtained was dissolved in hexane and filtered to remove insolublematerial; the hexane was subsequently removed by evaporation in vacuoand the S-(2,3,5-trichloro-- -4-pyridyl)isobutylxanthate was recoveredas a pale yellow, viscous oil having a refractive index (n) of 1.6044.Elemental anaylsis calculated for c n' cl uos, (percent): C, 36.4; H,3.02; N, 4.24; CI, 32.2. Found (percent): C, 36.3; H, 3.45; N, 4.35; Cl,32.7.

Example S-(2,3,5-trichloro-4-pyridyl)sec.- butylxanthate millilters-pyridyl)-sec.-butylxanthate Solutions of2,3,5trichl0ro-4-methylsulfonylpyridine (26 0 grams, 0.10 mole) in 100milliliters of acetone and sodium sec.-butylxanthate (18.0 grams,

Example 1 1: S-(2,3,5-trichloro-4-pyridyl)amylxanthate Solutions of2,3,5-trichloro-4-methylsulfonylpyridine (26.0 grams 0.10 mole) inmilliliters of acetone and potassium amylxanthate (18.0 grams, 0.10mole) in 400 milliliters of acetone were combined and the resultingreaction mixture was subsequently treated according to the proceduresset forth in Example 9. As

a result of these operations, there was obtained the desired S-(2,3,5-trichloro-4-pyridyl)amylxanthate prod uct as a pale yellow,viscouseliquid having a refractive index (n) of 1.5574. The identity ofthe structure was confirmed by nuclear magnetic resonance spectrometry.Example thate The reaction of a solution of 2,3,5-trichloro-4-methylsulfonylpyridine (26.0 grams, 0.10 mole) in 100 milliliters ofacetone with a solution of potassium hexyl-xanthate (23.0 grams, 0.11mole) in 400 milliliters of acetone was carried out in accordance withthe procedures in Example 9, except that the reaction time was for aperiod of 15 hours. Treatment of the resulting reaction mixturesubstantially as set forth in Example 9 resulted in the recovery of thedesired S-(2,3,5- trichloro-4-pyridyl)-hexylxanthate product as a paleyellow, viscous oil having a refractive index (n of 1.5627. The identityof the structure was verified by nuclear magnetic resonancespectrometry. Example 13:S-(2,3,5,6-tetrachloro-4-pyridyl)isopropyl-xanthate A solution ofpentachloropyridine (26.0 grams, 0.10 mole) in 100 milliliters ofmethylene chloride and 100 milliliters of acetone was combined with asolution of sodium isopropylxanthate (16.0 grams, 0.10 mole) in 100milliliters of water and the resulting two-phase reaction mixture wasstirred at ambient temperratures for a period of about 24 hours. Uponcompletion of the reaction, the methylene chloride phase was separated,dried over anhydrous sodium sulfate and evaporated under subatmosphericpressure to dryness. The solid residue representing the desiredS-(2,3,5,6-tetrachloro- 4-pyridyl)-isopropylxanthate product thusobtained was recrystallized from methano and the recrystallized materialmelted at 94 96 C. The identity of the structure was verified .bynuclear magnetic resonance spectrometry. Example 14: S-(2,3,5,6-tetrachloro xanthate A solution of pentachloropyridine (25.0 grams,0.10 mole) in 100 milliliters of. methylene chloride and 100 12:S-(2,3,5-trichloro-4-pyridyl)hexylxan- -4-pyridyl iso butylmillilitersof acetone was combined with a solution of ample l3 resulted in therecovery of the desired S- S( 2,3 ,5 ,6-tetrach1oro-4- tures for aperiod of about 44 hours. Subsequent sepav ration of the organic phaseand treatment thereof according to the procedures of Example 13 resultedin the recovery of the desired S-(2,3,5,6-tetrachloro-4-pyridyl)amylxanthate as a dark viscous liquid having a refractive index(n) of 1.5964. Elemental analysis calculated for C H CLNOS (percent): N,3.70. Found (percent): N, 3.69.

Example 16: S-(3,4,5,6-tetrachloro-2-pyridyl)ethylxanthate A mixture ofpentachloropyridine (25.0 grams, 0.10 mole) and potassium ethylxanthate(17.0 grams, 0.11 mole) in 100 milliliters of dimethylformamide washeated with stirring at a temperature of about 85 C. for about 4 hours.Upon completion of the reaction, the reaction mixture was cooled to roomtemperature, poured into water, and filtered to remove the brownprecipitate formed during the course of the reaction. The precipitate.was extracted with a solution of hot methanohfiltered to removeinsoluble products and concentrated by evaporation under subatmosphericpressure to yield the crude product as pale yellow crystalsmelting at485 1 C. Recrystallization of the crude product from methanol yieldedthe purified S-(3,4,5,6- tetrachloro-Z-pyridyl)ethylxanthate; therecrystallizzed product melted at 5153 C. The identity of the structurewas confirmed by nuclear magnetic resonance spectrometry.

In a manner similar to that described in Examples 1-65, there areobtained, inter alia, the following pyridylxanthate compoundsuponreaction of the respective corresponding polychloro-4-alkylsulfonylpyridine or pentachloropyridine reactant with the appropriatealkylxanthic acid reactant:

S-(2,3,5,6-tetrachloro-4-pyridyl)pentadecylxanthate, molecular weight of519;

S-(2,3,5,6-tetrachloro-4-pyridyl)octadecylxanthate, molecular weight of561;

S-(2,3,5,6-tetrachloro-4-pyridyl)eicosylxanthate, molecular weight of589;

S-(2,3-dichloro-4 pyridyl)sec.-butylxanthate, molecular weight of 296;

S -(2,3,5,6-tetrabromo-4-pyridyl)hexylxanthate, molecular weight of 571;

S-(2,5-dibromo-4-pyridyl)octylxanthate, molecular weight of 441; v i

S-(2,3,5-trichloro-4-pyridyl)decylxanthate, molecular weight of 414.5;

S-(2,3,5,6-tetrabromo-4-pyridyl)decylxanthate, molecular weight of 627;

S-(2,3,5,-tribromo-4-pyridyl)dodecylxanthate, lecular weight of 576;

S-(2,5-dichloro-4-pyridyl)tetraclecylxanthate, molecular weight of 436;

S-(2,3,5,6-tetrabr0mo-4pyridyl)hexadecylxanthate, molecular weight of711;

S-(2,3,5-trichloro-4-pyridyl)hexadecylxanthate, molecular weight of498.5;

In a manner similar to that described in Example 16, there are obtained,inter alia, the following 2- pyridylxanthate compounds upon the reactionof pentachloro-pyridine and the respective corresponding alkylxanthicacid reactant in the presence of dimethylformamide:

S-(3,4,5,6-tetrabromo-2-pyridyl)hexylxanthate, molecular weight of 571;S-(3,5-dibromo-2-pyridyl)octylxanthate, molecular weight of 441;

S-(3,5,6-trichloro-2-pyridyl)decylxanthate, molecular weight of 414.5;

S-(3,4,5,6-tetrabromo2-pyridyl)decylxanthate, mo-' lecular weight of627;

S-(3,4,6-tribromo-2-pyridyl)dodecylxanthate, lecular weight of 576;

S-(3,S-dichloro-Z-pyridyl)tetradecylxanthate, molecular weight of 436;

S-(3,4,5,6-tetrabromo-2-pyridyl)hexadecylxanthate, molecular weight of711;

S-(3,5,6-trichloro-2-pyridyl)hexadecylxanthate, molecular weight of498.5;

S-(3,5-dibromo-2-pyridyl)octadecylxanthate, molecular weight of 581;

S-(3,4,5,6-tetrabromo-2-pyridyl)eicosylxanthate, molecular weight of767;

S-( 3 ,5 ,6-tribromo-2-pyridyl)eicosylxanthate, molecular weight of 688;

S-(2,5-dibromo-4-pyridy1)octadecylxanthate, molecular weight of 581;

S-(2,3,5,6-tetrabromo-4-pyridyl)eicosylxanthate, molecular weight of767; v

S-(2,3,5-tribromo-4-pyridyl)eicosylxanthate, molecular weight of 688;

The products of the present invention are suitable for use asantimicrobialsand herbicides. For any of these uses, the unmodifiedcompounds can be employed. Alternatively, the compounds can be dispersedon an inert finely divided solid to prepare dust compositions. Thelatter dust compositions can be dispersed in water with or without theaid of a wetting agent and the resulting aqueous dispersions employed assprays. In other procedures, the compounds can be employed as aconstituent in edible oils or in other oils or solvents, or as aconstituent in solvent-in-water or water-insolvent emulsions ordispersions which can be employed as sprays, drenches or washes. Goodresults are obtained with methods employing and compositions containingeffective amounts of one or more of the compounds hereof. Generally,these amounts range from about 4.0 to about 500 parts per million of oneor more of the compounds.

1n representative operations, each of the S-(2,3,5,6-tetrachloro-4-pyridyl )ethylxanthate, S-( 2,3 ,5 ,6-tetrachloro-4-pyridyljsec.-butylxanthate, and S-(2,3,5,6-(tetrachloro-4-pyridyl)n-pentylxanthate compounds givescomplete control and kill of powdery mildew on cucumber (Erysiphecichoracearum) while each of theS-(2,3,5,6-tetrachloro-4-pyridyl)isopropylxanthate andS-(2,3,5,6-tetrachloro-4- pyridyl)isobutylxanthate compounds givessubstantially complete control of the same when one of the above-namedcompounds is separately applied to the environments containing andsupporting the disease organisms at a concentration of 150 parts permillion by weight. I

Through the separate use of one of the S-(2,3,5,6-

tetrachloro-4-pyridyl )sec.-butylxanthate, S-(2,3 ,5 ,6-tetrachloro-4-pyridyl)ethylxanthate and S-(2,3,5,6-tetra-chloro-4-pyridyl )isopropylxanthate compounds of the compounds ofthe present invention as sole toxi-' cant per million parts by weight ofultimate treating composition were prepared and separately applied tothe environments containing and supporting thriving members of one of avariety of microbial organisms. The results of the evaluations of thecompounds tested at the above concentration and the percent control ofthe organisms treated are set forth in the following table:

ture for about 3 hours, poured into ice water, and the resultingprecipitate representing the desired product is filtered off. Otherstarting materials of this type are similarly prepared by utilizing thismethod with the appropriate chemical analogs.

Alkylxanthates of the type employed as starting materials in the presentinvention are known and can be prepared by conventional methods orreadily obtained from commercial sources.

We claim:

1. A method which consists essentially of reacting a pyridine compoundcorresponding to the formula with an alkali metal salt of analkylxanthic acid of the formula v in the presence of an inert liquidsolvent as a reaction medium from about 20 C to about 40 C. for a periodCompound Percent kill and control of number Subject compound P4) T.m M.pRs. 0.1. S.a. 0.1 U4) 1S-(2,3,5,6-tetrachloro-4-pyridyl)n-pentylxanthate 100 100 50 100 50 50 0S-(2.3,5-trichloro-4-pyridyl)amylxanthate 100 100 100 100 100 100 00 0 3S-(2,3.5-trichloro-4-pyridyl)hexylxanthate.. 100 100 100 100 100 50 5050 4 S-(2,3,5-trichloro-4-pyridyl)sec.-butylxanthate 100 100 100 100 10050 50 0 5 S-(2.3,5trichloro-4-pyridyDisobutylxanthate 100 100 100 100100 100 100 100 6 S-(2,3,5,6 tetrachlor0-4-pyridyl)isobutylxanthate 0100 100 100 100 100 0 100 7...S-(3,4,5,6-tetrachloro-2-pyridyl)ethylxanthate t 50 100 100 100 50 100 050 8... S-(2.3,5-trichloro4-pyridyl)isopropylxanthate 0 0 100 0 0 50 0 09... S-(2.3,5,6-tetrachloro-4-pyridyl)isopropylxanthate 0 0 100 0 0 0 00 10 S-(2,3,6,6-tetrachloro-4-pyridyl)2-methylbutylxanthate; 0 100 10050 100 50 100 0 NoTE.P.p.=Pullularia pullulans; T.m.=l'richophylonmentagrophytes; M;p.= l1ycobacterium phlei; B.a.=Bacz'llus subtilis;C'.f.=Cephaloatacus fragrans; S.a.=Staph lococcus aureus;C.I.=Ceratocyatis IPS, C.p.=Candida pelliculosa.

are contacted with compositions containing one of the above-namedcompounds at a concentration of 4.0 parts per million by weight.

The pentachloropyridine compound employed as a starting material as setforth in the foregoing teachings can be prepared in accordance withknown procedures. For example, See US. Pat. No. 3,359,267.

The polychloro-4-alkylsulfonyl pyridine compounds employed as startingmaterials in the present invention are prepared by known methods. In arepresentative operation, 2,3,5,6-tetrachloro-4-(methylsulfonyl)pyridineis prepared'by adding hydrogen peroxide (27.0 grams) dropwise to asolution of 2,35,6- tetrachloro-4-methyl-thiopyridine (20.0 grams)' and100 milliliters of glacial acetic acid. The resulting reaction mass isstirred and maintained at reflux tempera:

of time sufficient to give the corresponding pyridylxanthate product ofthe formula 5 l s-i s oqi j n \N j wherein, in the above formulas,

tonitrile, carbon tetrachloride, chloroform, benzene, toluene, ethylmethylketone, methanol, ethyl acetate and methylene chloride.

4. The method of claim 1 wherein the pyridine and alkylxanthic acidreactants are employed in essentially equimolarproportions.

5. The method of claim 1 wherein the pyridine reactant is2,3,5,6-tetrachloro-4-methylsulfonylpyridine.

a: a I: n:

22x2? 7 m m PATENT F C CERTIFICATE O CORRECTION mama. 336M608 m ember 9,1973 Invlntofls) s ph E. Dunbar ar md Johow. Zomba It is oomified thaterror appears in the abovwidon tifiad patent and that said Louto'miatentare hereby fififlli'fifi'llfifi m"; oolow:

--- CORREGTIONS CONTINUE Mm Column 5 lino 5 8, "amylsis" 'ohould road"analysis".

Column 5, 3.111% 63 and gh, delete "miliiltdrs -pyr1dyl)--soc.,-butylxanthate (n Cl".

I Column 6, lines 7, 2!, and 3 (1 should read x-6?)",

Column 6, line 20, "viacouseliquid" should read "viscous liquid".

. Columg 6, line 46, "temperratures" should read "temper'a- I turesCoiumn 7, iineo 3 and 18, "(r1 2 should read "(r1 9)",

column 7 11nd 8, "ncr stunzaea" should read "rocrydtallizod Column 7lind' B "1-65" should read "lb-15".

Col 8, line 1, "Si-(2,3,5,6-tetro.bromo-4pyridyl)'" should road"Pr-(3,3,5,6-tetrabromo-4-pyr1dyl)".

Co 8 lino 60, delete the opening parenthesis before"totmcmormM-pymdyl)".

Golumn 9 line 6, "tetra-chloro" should road "tetrachloro".

Column 10 footnote "Cephaloatscus" should read Cephaloascus o L $15,883V I J Po-ww mm mmm mmm It 1a cmfitifified that mm: aypwm in 213 262mmwwmmma patent and that flaw mamas; Eamm mwmzzm zg mm Mimi:

.Colunm 1, between limw m amfi 129 853W fi 1m tha stmcimml formulasheulcfi. be at sm Ewing; pmition as, follaw:

(301mm 3, 11m: 5%, "farm" 331mm Wm "*irm" Column 3,, line 5% "c 3%89"mmm mm "c, 32.89".

Column line 3 6 after wpyriayl mam should be a. closing paren'tmsm.,

Column 13.13% 12 "ml" shoulci read "21% Colurm linens 29 1mm; m (11 m, 5Column t line 2 afwr 1% 3H6 delaw {$2 0 Column n; line 01 *B y" flhmlldmad "byh (301mm 5 lin 13, pyridlfi? should wad. "pyriyl". Colunm 5 line21 A5 29 aahmld wad; $542229.a

(301mm 5 line 51 QYfiSfifiEl 5141mm read "pressure". Column 5,, line 5(12 anem a mm "(11 Signed and sealed this Mr day at Octobr 1974.

(SEAL) Attesiz:

McCOY always JR ca MARSHALL DANN Atteating, Officer Commissinner 0fPatents

2. The method of claim 1 wherein the reaction mixture is maintained at atemperature of from about 20 to about 40* C. for about 1 hour to about30 hours.
 3. The method of claim 2 wherein the reaction medium comprisesinert carriers selected from the group consisting of water, acetone,dimethylformamide, acetonitrile, carbon tetrachloride, chloroform,benzene, toluene, ethyl methyl ketone, methanol, ethyl acetate andmethylene chloride.
 4. The method of claim 1 wherein the pyridine andalkylxanthic acid reactants are employed in essentially equimolarproportions.
 5. The method of claim 1 wherein the pyridine reactant is2,3,5, 6-tetrachloro-4-methylsulfonylpyridine.